Merge pull request #4082 from matrix-org/rav/fix_pep8

changelog.d/4082.misc

scripts-dev/tail-synapse.py

scripts/synapse_port_db

setup.cfg

synapse/config/repository.py

synapse/crypto/keyclient.py

synapse/federation/federation_server.py

synapse/rest/client/v2_alpha/auth.py

synapse/rest/media/v1/preview_url_resource.py

synapse/storage/registration.py

tests/config/test_generate.py

tests/events/test_utils.py